1. Field of the Invention:
This invention relates generally to multiparty telephone lines and, particularly, to a device for providing selected ringing of a specific party in a multiparty telephone system. Different ringing frequencies are used to alert only the intended party in the multiparty system of an incoming telephone call.
2. Description of the Prior Art
Multiparty telephone systems involve a number of telephone stations or subscribers which share a single pair of line conductors extending from a central office facility. The line may be seized by any one of the telephone sets of the subscribers to originate an outgoing call. The ringing current for an incoming call is coded in one of several different frequencies to alert the intended receiver of the incoming call. For example, the ringers of a particular subscriber would be resonant to a particular frequency. This prior art party line system requires that the party line customers be provided with phones having specifically designated frequency ringers.
However, in the present deregulated environment it is mandatory that the customer by able to buy and own his own equipment by simply going to any FCC approved manufacturer or supplier for his phone. These phones come either with ringers that will work only on a 20 Hz ringing frequency, or with electronic ringers which will work on any frequency. Therefore, neither of these two phones are suitable as primary ringers in a frequency selected party line environment.